Sleep for more than 8 hours to stay slim

Adding a few hours sleep to your night may prevent you from gaining weight.

A new study has found that sleeping more than nine hours a night appears to suppress genetic factors that lead to weight gain.

In contrast, getting too little sleep seems to have the opposite effect.

Previous research has shown an association between poor sleep and obesity, but the new findings reveal a complex interaction between sleep and genetic factors linked to body weight.

Scientists made the discovery after studying 1088 pairs of identical and non-identical twins.

Twin studies help researchers unravel genetic and environmental influences. Only identical twins share the same genes, and are therefore subject to the same genetic effects, so differences between them are likely to be due to environmental factors.

The study found heritability of body mass index (BMI) – a measurement relating weight and height – was twice as high for short than for long sleepers.

For twins sleeping less than seven hours a night, genetic factors accounted for 70 per cent of differences in BMI. In twins averaging more than nine hours` sleep, only 32 per cent of weight variations could be attributed to genes.

`The results suggest that shorter sleep provides a more permissive environment for the expression of obesity related genes,` WAtoday quoted Nathaniel Watson, from the University of Washington, who led the US study, as saying.